Vehicle fueling service stations in some regions of the United States, i.e. those regions where only Phase I (i.e. non-Phase II) vapor recovery is mandated, and in many other countries, operate with limited or no restrictions on release of fuel vapors into the environment, e.g. including fuel vapors generated by evaporation of liquid fuel into the ullage space of vehicle and underground storage tanks (“UST”), and then displaced from the tank by entering liquid fuel during filling. This loss of fuel in its vapor state is recognized as a detriment to the environment. Over a period of fueling operations, it can also represent a substantial loss of product and potential profit to the service station owner and operator.